Section Of Shore Research Articles

Wrack line formation and composition on shores of a large Alpine lake: The role of littoral topography and wave exposure.

Wrack lines are a key formation along shorelines that provide organic matter and bring ecological diversity to the local environment. Although wrack line formation has been extensively studied along marine beaches and estuaries, in contrast, knowledge about the environmental variables that promote wrack line formation within inland lakes is widely lacking. In one of the first studies to focus on wrack line formation on lakesides, we analysed the dimensions, volume, elevation and particulate composition of 36 wrack lines across 20 shore sections of a large, oligotrophic Alpine lake with natural water level fluctuations (Lake Constance-Obersee). Using multivariate partial least squares (PLS) regression, we identified the key environmental variables that drive wrack accumulation in lakeside areas. Our results demonstrate that wrack line volume increased with (1) the width of the eulittoral zone as an indicator of the swash conditions (up-rush vs. down-wash), (2) high exposure to wind waves as indicated by the total effective fetch, (3) high exposure to ship waves (catamaran ferry), and (4) the width of the sublittoral zone as an indicator of the availability of source material (Chara spp.) and of the wave energy dissipation rate of the incoming deep water waves. Sediment texture played only a minor role. Wide eulittoral zones and high ship wave exposure favoured high proportions of lake-borne components (Chara remains, mollusc shells), while the reverse was true for land-based components. Anthropogenic wastes were only present in small proportions. We discuss four main factor groups influencing the amount of wrack in marine beaches and on lakeshores considering similarities (waves, breakers, swash, dissipation, relief) and differences (tides vs. annual water level fluctuations) of the two systems, and point out research gaps. We demonstrate that wrack line formation is also important in large inland lakes and can be analysed using basic ideas from relevant marine studies.

A novel ecological risk assessment approach applied to Jiangsu coastal zone, China

Natural and anthropogenic risk factors contribute to ecological risks in coastal zones; however, the response of ecological entities (receptors) to disturbances varies with the risk source. We used the risk causal law as a guide to construct an ecological risk assessment method for Jiangsu coastal zone, China, with different ecological receptors as the research subjects. We screened the evaluation indicators for natural and anthropogenic risks, validated the evaluation results, and designed a method to map the integrated coastal ecological risk. The five typical ecological receptors exhibited different risk responses when faced with different disturbances. Among the natural risks, invasive species and seawater pollution had the largest differences in risk values. Of the anthropogenic risks, the largest differences in risk values were for reclamation sea farming and industry. The results of the habitat risk assessment model, which were based on the exposure–consequence framework, and those of the hazard–vulnerability–damage model showed a strong positive correlation. Furthermore, the T-test results were tested with P values of less than 0.05, and were not significantly different at the 95% confidence level; thus, the results were valid. The variability in the evaluation results of different ecological receptors was used to map the integrated ecological risk. High- and very-high-risk areas were distributed along the coastline and the edge of the radiating sand ridge, and moderate-risk areas were distributed within the high-risk mudflat areas. The ecological risk values were quantified for each shore section; very-high-risk areas were mainly distributed in the central and estuaries shore sections, and moderate-risk areas were mainly distributed in the southern shoreline sections. The exposure and consequence values calculated using InVEST-HRA model were used to select ten primary factors represented by coastal erosion and sewage discharge as well as five secondary factors represented by green tides and coastal engineering. Finally, we suggested future ecological protection and risk prevention measures based on the shore sections and primary and secondary factors. This study takes the causal relationship of the risk occurrence process as a guideline, and combines the reflected difference characteristics among the risk elements to provide scientific support for the practice of ecological risk prevention and governance in the coastal zone.

Warning water level determination and its spatial distribution in coastal areas of China

Abstract. The warning water level is the default water level at which storm surges may occur along a coast and indicates a stage of alert. This level forms the basis for storm-surge forecasting, and prewarning is an important reference for governments and aids in the decision-making process for storm-surge prevention and disaster risk mitigation. The warning water level has four categories (blue, yellow, orange, and red) based on water level observational data. Taking into account the actual defense capability of the shore, we determined the warning water level by comprehensively analyzing factors, including the high water level at the typical return period of each shore section, wave exposure degree and defense capability of storm-surge protection facilities, and the shore-section importance level. Here, we proposed a quantitative method for determining the warning water level, and the application of this method was introduced by determining the warning water level at the shore section of Zhifu District (Yantai City, Shandong Province, China) as an example. We analyzed the spatial distribution characteristics of the warning water levels for 259 shore sections along the coast and revealed their current marine disaster prevention capabilities. Our findings provide a valid direction for determining future warning water levels and a reliable scientific reference for redetermining warning water levels in coastal areas while improving marine disaster prevention and protection capabilities.

Effect of landfall location and coastal topography on surge response in the Northern Bay of Bengal

Storm surges caused by frequent cyclone events have posed severe threats to the inhabitants of the northern Bay of Bengal. In this study, a high-resolution, two-dimensional, hydrodynamic storm surge model was developed using the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) to investigate storm surges in the Bay of Bengal. After validation, the storm surge of the study area was simulated for 11 idealized cyclone cases, the tracks of which were approximately perpendicular to the head of Bay of Bengal when landing at high-tide and low-tide time, respectively. The simulation results show that when landing at the high-tide time, the cyclone produced a peak surge height of about 85% of that when landing at the low-tide time, on average. It is also shown that when cyclone landed during the low-tide time, there was a delay of about 90-130 min for the arrival time of peak surge at the right side of the landfall position, compared with that landed during the high-tide time. Finally, we found that, for the area of the head of the bay, the surge response in the middle-eastern part was weak than that in other parts. This study demonstrates the importance of including the tide-surge interaction in the simulation of storm surge and provides the difference of the surge responses between different shore sections of the study area, which may be useful for the prediction and mitigation of the storm surge disaster.

Logical Information Model for Prediction of Reservoir Slope Stability in Water Environment Control Project

Zhang, G.Q.; Feng, W.K.; Qi, Y.; Zhou, Y.J., and Yang, J., 2020. Logical information model for prediction of reservoir slope stability in water environment control project. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 587-592. Coconut Creek (Florida), ISSN 0749-0208.The complex structure of the bank slope in the reservoir area is combined with the continuous undercut of the river to transform the side slope of the bank slope, which poses a certain threat to its stability. Water environment Treatment Engineering the actual data of typical slope collapse and deformation of reservoir are used as the basis, and a new quantitative theory method, logical information method, is adopted, which realizes higher accuracy by establishing logical information model and fuzzy logic expansion of the model. Through the prediction of the stability of the shoreline slope of the whole reservoir area, the stability of the natural and post-water rainstorm is statistically different. It is best to carry on the experimental analysis to the model, the result shows: the natural condition subordinate the potentially unstable shore section is very few, the vast majority is basically stable. In the case of heavy rains after water storage, the proportion of unstable shore segments rose to 9.4%, and the stable shoreline fell to 19.2%. The results show that the logic information model has a certain guiding effect on the prediction of the stability of reservoir bank slope of water Environment control project.

Мониториг опасных береговых процессов Цимлянского водохранилища с использованием ГИС-технологий

In the article, the degree of displaying dangerous exogenetic geological processes (abrasion, landslide, erosion) of the Tsimlyansk Reservoir at the present stage of reforming its shores is assessed. A new original methodology for monitoring morphological and morphometrical characteristics of different shore types of the reservoir, using unmanned aerial vehicles (UAV) and Agisoft Photoscan tooling is proposed. For a number of shore sections of the Tsimlyansk reservoir, assessment of consequence for stirring up abrasion activity being expressed in stepping back the edge of shore steeps and reducing land fund is carried out. In the automated information system of water bodies state monitoring, a compulsory index is monitoring of erosion dismemberment. Methods to carry out erosion processes monitoring in water protection zones (WPZ) of water bodies using software and apparatus complex, created on the base of UAVs and GIS-technologies are developed and tested, an optimal type of digital elevation models (DEM) for assessing erosion network density is determined. Based on series of photographs carried out by UAVs by the DEMs and orthophotomaps, created using Agisoft Photoscan software, the relief erosion forms are determined. Morphometrical characteristics of the relief erosion forms are also measured, the erosion network density (K) for a number of plots in the water protection zones of the Tsimlyansk Reservoir coast is determined. In the protection zone of the Tsimlyansk Reservoir, comprehensive analysis is carried out, assessment of demographic load on the coastal area of the reservoir is conducted. Territorial zoning according to the degree of demographic load is carried out and it will allow in the future to organize planning timely measures for protecting coastal zones. The results obtained in the course of work allowed to make conclusions for the sections of the reservoir water protection zone most subject to anthropogenic activity and to propose a package of measures for its reducing.

Effects of a retaining wall and an artificial embankment on nearshore littoral habitats and biota in a large Alpine lake

The littoral zones of many Central European lakes are severely altered by lake-side retaining walls. These are suspected to impair littoral biota due to the reflection of incoming wave energy. We conducted a comparative study (armoured shore with a retaining wall and a restored shore with a wedge-shaped cobble embankment vs. a pristine shore) at a wind-exposed shore section of Lake Constance. The retaining wall had a number of significant remote effects on the littoral zone, i.e. increased near-bottom current velocities, higher bed-load transport rates, coarsening of surface sediments, reduction in phytomass density, reduction in total densities and number of taxa of macroinvertebrates as well as a significant decline in the percentages of Limnomysis benedeni Czerniavsky, 1882, Ostracoda, Corbicula fluminea O.F. Muller, 1774, Dreissenapolymorpha (Pallas, 1771) and other Bivalvia. However, the significantly affected zone had a rather narrow width of ~ 3 m. Shore restoration measures are needed to remediate negative effects of retaining walls and re-establish ecological conditions that are comparable to those of pristine shores. We recommend a more site sensitive sampling strategy, e.g. for macroinvertebrates in context with the ecological quality assessment under the European Water Framework Directive.

Comprehensive Evaluation of Coastline Development and Utilization Intensity—A case study of Dafeng China

The coastline plays an important role in the development and utilization of resources in the coastal waters and ecosystem protection. With the continued active development of coastal development and utilization activities, the development and protection of the coastline has become a major issue of the coastal zone. In order to scientifically and effectively assess the degree of coastline development and utilization, based on the characteristics of coastal wetland ecological stability, shoreline utilization disturbance characteristics and artificial dam dynamic change, a comprehensive evaluation model for coastline development and utilization intensity was established, and China Dafeng was taken as an example to conduct analytical evaluation. The results show that the total length of the Dafeng coastline is about 79.3km, and the coastal salt marsh vegetation and tidal flat landforms are widely distributed. The average depth of the coastal wetlands can reach 3.4km; the port, industry and other strong interference shores account for 16.2% of the total length of the shoreline. The moderately disturbed shores accounted for 61.8% of the total length of the shoreline, and the coastal natural attributes were better than the total length of the shoreline of 22.1%. Since 1973, the artificial levees of the Dafeng Coast continued to advance to the sea, with an average approach distance of 9.2km, which can up to 14.7 km; Dafeng coastline has significant spatial differences in development and utilization intensity. The lengths of the five types of high-strength, medium-high-strength, medium-strength, medium-low-intensity and low-intensity coastlines are 12.1km, 13.4km, 17.5km, and 21.6km, 14.7km, respectively. The high-strength and medium-high-strength development and utilization shore sections are mainly concentrated in the port shore and industrial shore sections centered on Dafeng port.

Quantitative Evaluation of Artificial Interference Intensity on Coastline——A Case Study of Haizhou Bay in China

Based on the two characteristics of the sensitivity nature of coastline to the artificial interference and the intensity of the human activity interference, this paper constructs an evaluation model of artificial interference intensity on coastline, and takes the Haizhou Bay of China as an example for analysis. The results show that the coastline of Haizhou Bay is 77.75 km long and the coastal areas are affected by human development activities to varying degrees. The lengths of the middle section of high level, medium-high level, medium level, medium-low level and low level interferences are 18.13km, 11.12km, 17.15km, 28.31km, and 3.04km respectively. The high level interference and medium-high level interference shore sections are mainly distributed in the three coastal areas of Lanshangang district, Binhai new town of Ganyu district, and Binhai new town of Lianyun district. Meanwhile, the effectively recognizing the intensity of interference received from coastlines, which can provide the basis for the implementation of more scientific and efficient coastal protection management.

The role of nearshore slope on cross-shore surface transport during a coastal upwelling event in Gulf of Finland, Baltic Sea

The wind induced coastal upwelling process often contains a mid-phase that involves coherent long-living cross-shore surface jets of cooler water. These jets extend to 40–45 km from the coast and tend to start from particular coastal locations. We develop a simple method for evaluating the depth in the water column from where the upwelled water originates. We also test the hypothesis that the development of cross-shore surface jets may be triggered by some permanent characteristics such as the bathymetry or the slope of the nearshore seabed. The analysis is performed for a strong and well-documented upwelling in the Gulf of Finland, the Baltic Sea, using high resolution bathymetry data, satellite derived sea surface temperature, surface currents measured by in situ drifters, and properties of water masses in two sampling locations. The results indicate that the cross-shore jets originate exclusively from the shore sections with much steeper slopes (>0.0075) than in the rest of the study area. The cooler water most likely origins from intermediate water masses at depths between 15 and 30 m. The resulting identification of the source depth of the upwelled water and its spatial location assists in understanding the flux of nutrients during upwelling events and their link to the onset of cyanobacteria blooms.

SPATIAL-TEMPORAL DETECTION OF CHANGES ON THE SOUTHERN COAST OF THE BALTIC SEA BASED ON MULTITEMPORAL AERIAL PHOTOGRAPHS

Digital photogrammetry and remote sensing solutions applied under the project and combined with the geographical information system made it possible to utilize data originating from various sources and dating back to different periods. Research works made use of archival and up-to-date aerial images, satellite images, orthophotomaps. Multitemporal data served for mapping and monitoring intermediate conditions of the Baltic Sea shore zone without a need for a direct interference in the environment. The main objective of research was to determine the dynamics and volume of sea shore changes along the selected part of coast in the period of 1951-2004, and to assess the tendencies of shore development in that area. For each of the six annual data sets, the following were determined: front dune base line, water line and the beach width. The location of the dune base line, which reflects the course of the shoreline in a given year was reconstructed based on stereoscopic study of images from each annual set. Unidirectional changes in the period of 1951-2004 occurred only within 10% of the examined shore section length. The examined shore is marked by a high and considerable dynamics of changes. Almost half of the shore, in particular the middle coast shows big changes, in excess of 2 m/year. The limits of shoreline changes ranged from 120 to -90 m, and their velocity from 0 to 11 m/year, save that the middle and west parts of the examined coast section were subjected to definitely more intense shore transformations. Research based on the analysis of multitemporal aerial images made it possible to reconstruct the intermediate conditions of the Baltic Sea shoreline and determine the volume and rate of changes in the location of dune base line in the examined period of 53 years, and to find out tendencies of shore development and dynamics.

SPATIAL-TEMPORAL DETECTION OF CHANGES ON THE SOUTHERN COAST OF THE BALTIC SEA BASED ON MULTITEMPORAL AERIAL PHOTOGRAPHS

Abstract. Digital photogrammetry and remote sensing solutions applied under the project and combined with the geographical information system made it possible to utilize data originating from various sources and dating back to different periods. Research works made use of archival and up-to-date aerial images, satellite images, orthophotomaps. Multitemporal data served for mapping and monitoring intermediate conditions of the Baltic Sea shore zone without a need for a direct interference in the environment. The main objective of research was to determine the dynamics and volume of sea shore changes along the selected part of coast in the period of 1951-2004, and to assess the tendencies of shore development in that area. For each of the six annual data sets, the following were determined: front dune base line, water line and the beach width. The location of the dune base line, which reflects the course of the shoreline in a given year was reconstructed based on stereoscopic study of images from each annual set. Unidirectional changes in the period of 1951-2004 occurred only within 10% of the examined shore section length. The examined shore is marked by a high and considerable dynamics of changes. Almost half of the shore, in particular the middle coast shows big changes, in excess of 2 m/year. The limits of shoreline changes ranged from 120 to -90 m, and their velocity from 0 to 11 m/year, save that the middle and west parts of the examined coast section were subjected to definitely more intense shore transformations. Research based on the analysis of multitemporal aerial images made it possible to reconstruct the intermediate conditions of the Baltic Sea shoreline and determine the volume and rate of changes in the location of dune base line in the examined period of 53 years, and to find out tendencies of shore development and dynamics.

Optimum or suboptimum methods of the slaughtering line relocation definition development

Despite the existing automation level of processes in coal mines, the uniform displacement of slaughtering line solution is still not under control. In the article proposed methods of optimal or suboptimal decision of this question. It is based on coal mining management system quality requirements. The aim of this development is to provide the achievement of the optimal level of productivity of the coal mining process at the expense of layup minimization. The cause of layup is convergence of the deads. Given virtual inaccuracy displacement control model of the shore sections overlap based on the proposed methods. It provides keeping, analysis and cognitive information visualization. Defined precision of level control shore displacement inaccuracy according to the Coal Mining Rules process.

AFLP genome scans suggest divergent selection on colour patterning in allopatric colour morphs of a cichlid fish

Genome scan-based tests for selection are directly applicable to natural populations to study the genetic and evolutionary mechanisms behind phenotypic differentiation. We conducted AFLP genome scans in three distinct geographic colour morphs of the cichlid fish Tropheus moorii to assess whether the extant, allopatric colour pattern differentiation can be explained by drift and to identify markers mapping to genomic regions possibly involved in colour patterning. The tested morphs occupy adjacent shore sections in southern Lake Tanganyika and are separated from each other by major habitat barriers. The genome scans revealed significant genetic structure between morphs, but a very low proportion of loci fixed for alternative AFLP alleles in different morphs. This high level of polymorphism within morphs suggested that colour pattern differentiation did not result exclusively from neutral processes. Outlier detection methods identified six loci with excess differentiation in the comparison between a bluish and a yellow-blotch morph and five different outlier loci in comparisons of each of these morphs with a red morph. As population expansions and the genetic structure of Tropheus make the outlier approach prone to false-positive signals of selection, we examined the correlation between outlier locus alleles and colour phenotypes in a genetic and phenotypic cline between two morphs. Distributions of allele frequencies at one outlier locus were indeed consistent with linkage to a colour locus. Despite the challenges posed by population structure and demography, our results encourage the cautious application of genome scans to studies of divergent selection in subdivided and recently expanded populations.

Reef demise and back-stepping during the last interglacial, northeast Yucatan

The elevation of reefs and coastal deposits during the last Interglaciation (MIS-5e) indicates that sea level reached a highstand of as much as 6 m above the present, but it is uncertain how rapidly this level was attained and how it impacted reef development. To investigate this problem, I made a detailed sedimentological analysis of a well-dated reef from the northeast coast of the stable Yucatan Peninsula. Two linear reef tracts were delineated which are offset and at different elevations. The lower reef tract crops out along northern shore for 575 m and extends from below present mean sea level to +3 m. The reef crest facies consists of large Acropora palmata colonies dispersed within a coral boulder-gravel and is flanked by an A. cervicornis-dominated reef-front and a large area of lagoonal framework formed by coalesced patches of A. cervicornis and Montastraea spp. Constituents in the upper centimetre of the lower tract are heavily encrusted by a cap of crustose corallines and, in places, are levelled by a discontinuous marine-erosion surface. The upper reef tract crops out ~150 m inland up to an elevation of +5.8 m and parallels the southern section of shore for ~400 m. It also consist of an A. palmata-dominated crest facies flanked by reef-front, back-reef and lagoonal frameworks. In this case, however, lagoonal frameworks are dominated by a sediment-tolerant assemblage of branching coralline algae. Also different is the lack of encrustation by corallines, and the infiltration of upper tract facies by beach-derived shell-gravels from regressive shoreface deposits above. These results indicate that the lower reef tract and lagoonal patch-reefs formed at a sea level of +3 m. Final capping by crustose corallines and discontinuous marine erosion indicates that the lower tract was terminated by the complete demise of corals on the crest but only patchy demise in the lagoon. Areas of continuous framework accretion between the lagoonal patch reefs and the upper reef-tract, however, require that the demise of this reef was ecologically synchronous with initiation of the upper reef-tract, which had back-stepped 100 m into the lagoon. In this new position, the upper tract developed a reef crest that corresponded to a final sea-level position of +6 m. Reef flat development at +5 m and large in-place colonies of A. palmata at the base of the crest unit indicate, however, that sea level must have risen rapidly from +3 to more than +5 m to accommodate back-stepping. This sea-level jump created a higher energy wave field that mobilized back-reef and lagoonal sediments, and the resulting high sediment flux eroded lagoonal framework and prevented the recovery of the submerged lower reef crest. So this single jump in sea level was responsible not only for reef demise and back-stepping but also for marine erosion and suppression of subsequent reef development—features that elsewhere have been used to support multiple sea-level excursions during the last interglacial.

Helminth communities of wood mouse ( Apodemus sylvaticus ) on the river Avena (Calabria, southern Italy)

Helminth parasites of woodmouse Apodemus sylvaticus were studied from May 1993 through to June 1994 on the River Avena (Calabria, southern Italy), which, as other Mediterranenan rivers, is dry for most of the year. Trapping sites were located in three different habitats of the river: slopes, shores and the riverbed. A total of 106 animals was captured and screened for the presence of helminths. Five endoparasitic species were detected: Corrigia vitta , Rictularia proni , Heligmosomoides polygyrus , Syphacia stroma and S. frederici . Four helminth species were recorded from the riverbed and shore sections, whereas only H. polygyrus and S. frederici were found on the slopes. Syphacia frederici occurred at every trapping site. The total prevalence was 25.5% and total mean intensity was 27.2 parasites/mouse. No statistical significant difference was found for both the prevalence and mean intensity of infection between either habitats or sexes, suggesting that, from the point of view of the helminth community, the study area should be considered as a single habitat.

Tepexpan revisited: A multiple proxy of local environmental changes in relation to human occupation from a paleolake shore section in Central Mexico

Building up a scenario of Late Pleistocene–Holocene environmental change and human–landscape interactions in Central Mexico – one of the key areas for the natural and cultural history of America – requires development of local paleoenvironmental reconstructions. We studied the Tepexpan section at the edge of Texcoco a paleolake, near the mouth of Teotihuacan Valley as a multiproxy record of the environmental dynamics at the shore in the Basin of Mexico throughout the period of human occupation. The section is located in an ecotone affected by intensive and variable geomorphic processes and includes lacustrine, fluvial and volcanic sediments as well as paleosols. Our chronological scale is based on 6 AMS 14C dates from pollen concentrates and paleosol organic matter. The lower segment of the section dominated by the lacustrine sediments yielded pollen spectra; in the upper segment the record is based on the pedogenetic characteristics of paleosols. Different proxies agree in demonstrating the general trend (although some reversals are apparent) of decreasing effective moisture since MIS3: it is reflected first in the increase of herbaceous pollen after 27 ka BP, the decrease of lake level, the cessation of lacustrine sedimentation and beginning of marsh soil development at 10 ka BP and finally, the shift from hydromorphic to dryland semiarid pedogenesis in the Late Holocene. We assume that this trend was climatically controlled, whereas the deposition of sedimentary layers enriched with tephra are related to the pulses of volcanic activity; the pedosedimentary features associated with the upper soil are human-induced. Comparing the proposed scheme of environmental change with the archaeological record we propose that the initial settlers, Late Paleolithic hunters, could have utilized the wet swampy meadows which expanded on the Basin bottom as the lake level lowered and provided the niche for large herbivores during the Pleistocene–Holocene transition. Development of agriculture and the network of permanent settlements are believed to be linked to the formation of well drained soils. In the methodological perspective the study shows the potential of ecotones as highly dynamic and sensitive systems that may archive valuable paleoecological records.

富士海岸における漂着ゴミの打ち上げ高

The aim of this study was to investigate a runup height of drifting litter due to waves on the cross shore between shoreline and sea embankment in the Fuji coast. Field investigations were performed by photographically recording debris in 3m×2m quadrilateral areas using a digital camera along transects extending from the shoreline to the sea embankment on a section of sandy beach. The number of drifting litter on the quadrilateral area was counted from the personal computer display inputted digital photograph, and arranged graphically by relating to the cross shore section. As the result it was found that, (1) the cross shore distribution of litter is not uniform and has a few peaks, (2) that the litter runup height at the first peak in the nearest shoreline is indicated with the surfsimilarity parameter using the maximum wave characteristics selected from the order of wave height before the field survey through the one year observed wave-record.

Coastline configuration disrupts the effects of large-scale climatic forcing, leading to divergent temporal trends in wave exposure

Both climate change and the North Atlantic Oscillation (NAO) may influence coastal systems by altering wave exposure. The effects of such climatic forcing are often coherent over relatively large geographic areas. Temporal trends in wave exposure at any particular shore are, however, the result of an interaction between site-specific fetch characteristics and changes in wind climate. This leads to contrasting trends in wave exposure at locations separated by no more than a few kilometres. Wave exposures were estimated at locations around a sea lough over 32 years to characterise these scales of variability. Locations separated by approximately 5 km had independent dynamics with respect to the temporal trend (correlation range −0.35 to 0.44) and to associations with the NAO (correlation range −0.18 to 0.40). Wave exposure can therefore be increasing for a section of shore while nearby areas have the opposite trend. Mean exposure at a location was not a good predictor of the temporal trend. More exposed sites were, however, sensitive to variations in the strength of the NAO. The reduction of large scale forcing to small-scale variability has implications for the detection and mitigation of potential climate change impacts.

Patterns of association between algae, fishes and grey herons Ardea cinerea in the rocky littoral zone of a Scottish sea loch

The distribution of dominant algae, Fucus vesiculosus and Ascophyllum nodosum, the associated fish community, and the spatial and temporal distributions of the main piscivorous predator, the grey heron Ardea cinerea, were studied on the rocky intertidal zone of Loch Etive, a sea loch on the Scottish west coast. Fucus- and Ascophyllum-dominated shores were not distributed randomly around the shore: the latter was especially common along the more sheltered shores and bays and on the finer substratum types. Coverage and frond length of Ascophyllum were greater than for Fucus. Fourteen fish species were caught in the intertidal zone. Numerically, the catch was dominated by four species caught in Fucus- and Ascophyllum-dominated habitats in both winter and summer: Spinachia spinachia, Pholis gunnellus, Taurulus bubalis and Zoarces viviparus. A higher species richness and fish abundance were recorded on Ascophyllum shores than on Fucus ones in both seasons. On Loch Etive, grey herons foraged exclusively in the intertidal zone usually as solitary, well-spaced individuals. The models suggest the number of foraging birds tended to increase with increasing total algal area (i.e. the two dominant species plus Fucus serratus) and with area of Ascophyllum and decreased with increasing area of Fucus and distance from the breeding colony. Adult grey herons showed a preference for foraging in Ascophyllum habitat and first-years showed no preference, suggesting that Ascophyllum-dominated areas are optimal foraging habitats for coastal-living grey herons. One section of shore was particularly important in establishing these habitat relationships: an Ascophyllum-dominated section with the largest intertidal area and where the highest number of foraging adults but no first-years were recorded. Future conservation and management considerations for the rocky intertidal zone should include associated fish communities and their predators, for which this habitat, and Ascophyllum-dominated areas especially, are of particular importance.